This invention relates to a tread for a pneumatic tire; more specifically, to a tread for light truck or automobile type vehicles.
A recent tread design was disclosed relating to a tread having an aquachannel. U.S. Pat. No. 5,176,766 issued Jan. 5, 1993, describes a directional tire having an annular aquachannel. The tire is commercially sold under the name Aquatred.RTM..
The above-referenced tire has demonstrated significant improvements in wet traction and hydroplaning characteristics.
Interestingly, in applications where vehicles have lightly loaded rear tires and more heavily loaded front tires, such as light trucks or vans, it has been established that the rear tires have a footprint that is loaded primarily in the central portion of the tread and the front tires have a tendency to wear rapidly on the outer side of the tire relative to the vehicle. This unique wear pattern resulted in the development of the Goodyear Wrangler GSA.RTM. tread pattern as shown in FIGS. 1-3.
The Wrangler GSA.RTM. tire has an asymmetric non-directional tread. The tread has three distinct tread zones, each zone provides unique wear and traction characteristics most suitably designed for light truck type vehicles.
This prior art tire exhibits two wide circumferentially extending zig-zag grooves which divide the tread into three tread zones. The outboard shoulder zone has a high net-to-gross ratio, the central zone has a slightly lower net-to-gross ratio than the outboard zone, and the inboard shoulder zone has the most open or lowest net-to-gross ratio. The tire exhibits excellent wear characteristics while also providing superb traction, both on and off the road.
Attempts to employ the Aquatred.RTM. aquachannel type groove in a light truck tire such as the Wrangler.RTM. GSA have created significant design tradeoffs or compromises. In particular, the employment of a wide circumferentially straight aquachannel, if positioned in the center of the tread, can induce rapid wear on the lightly loaded rear tires of vans or pickup trucks. Secondarily, the Aquatred.RTM.-type groove can also diminish the off-road or snow traction performance of the tread.
The present invention is directed to a tread particularly suitable for light truck or automobile use and having at least one, preferably two, aquachannel-type wide grooves; features of the novel tread design, when used in combination, can improve the overall wet traction of the tire without significantly diminishing the wear rate or the off-road and snow traction capability of the tire.